Telephone system



June 20, 1933. I R WQLF 1,914,391

TELEPHONE SYSTEM Filed July 22, 1952 Patented .lune 2i), 1933 UNETED STES NT TFCE RUDOLF VIOLE, F BERLIN, GERMLANY, ASSIGNOR TO STEIVIENS 8c HALSKE AKTIEN- l GESELLSCHAFT, OF WERNERWERK SIEMENSSTADT NEAR- BEB'LN, GERMANY TELEPHONE SYSTEM Application :filed July 22, 1932, Serial No. 623,959, and in Germany August 19, 1931.

The present invention relates to a circuit arrangement for switches in telephone systems. Y

The object of the invention is to speed up the testing operation as far as possible in telephone systems employing rapidly operating switches and this is achieved by the provision of devices which cause the driving magnet of the switch to iniiuence the test lim) relay inductively.

In arrangements of this type it may occur that when the switch is set on a line to be seized the driving magnet releases the locking pawly too soon with the result that n the switch wipers pass the line to be seized due to their momentum. This, according to the invention, is avoided by means of switching devices which retard the armature movement of the driving magnet when the switch is being set on a line to be seized.

n `.so modification of the invention but only a test circuit and the auxiliary winding of the rotary magnet of a switch influencing the testing relay have been diagrammatically shown. The subscriber of the subscribers station T in Fig. l is able to set up connections in known manner over a call finder AS and switches succeeding this call finder. Only the preparatory stages of such a connection are shown as the arrangement according to the invention is mainly used in these stages. lifhen the receiver is lifted in the subscribers station T and consequently the switch hook is actuated, relay R is energized over the subscribers lin-e loop in the following circuit:

earth, battery, resistance W1, contact 9t,

-lead, of the subscribers line, subscribers station T, a-lead of the subscribers line, contact Si, winding of relay R, earth. Relay R actuates its contacts 1r and 2r and the clos` ing of 1r marks the calling subscribers line 50 in the bank contact of the switch wiper 01 of the call finder AS. The following circuit for rclay Rl is complet-ed when contact 2r is closed: earth, battery, winding of relay Rl, cont-act 15p in normal position, contact 2r, 55 earth. Relay R1 is energized and closes its contacts 3111 and 4711. The closing of contact 3711 completes the following circuit for winding I of the rotary magnet D of the. call finder earth, battery, contact 3141, self interruptor contact 5d of the rotary magnet D, winding I of rotary magnet D, contact 6p, earth. The rotary magnet D is advanced in known manner in this circuit which is intermittently cut oil' by the contact 5cl 65 every time the magnet is energized. A winding Il of the rotary magnet D is connected in series with windings I and Il of the test relay P over contact Liri. ,Vhen the switch wipers cil-wl of the call nder AS encounter the calling line, the following circuit is closed: earth, battery, windings of relay T, contact lr, cl-wiper of the call finder AS, windings I and II of the test relay P, winding TT of therotary magnet D, contact 4711, earth. Then the rotary magnet has set its wipers to the calling line, an induced impulse is transmitted to winding TT of the rotary magnet on the opening of contact 5cl and this impulse accelerates the energization of the test relay P.

This relay which together with relay T operates in the above mentioned circuit opens its contact 6g; and by cutting olf the rotary magnet circuit brings said rotary magnet to rest. Contacts 10p and 117) switch through the line tothe succeeding group selector. The closing of contact 16g) causes relay R1 to relapse and the start line to be switched through to the succeeding call finder. Relay T, by actuating its contacts St and 9i disconnects the winding of relay R from the calling line and after contact l1 has been opened closes its own locking circuit by means of its contact 12t. The closingot contact 7 79 short circuits the high resistance winding II of the relay with the result that another call finder cannot be set to the incoming line.

In order to prevent the switch which operates with great speed from passing over the calling line contact due to its momentum after the release of the rotary magnet D and the therewith associated release of the locking pawl from the switch wheel, the release of the rotary magnet is retarded when the switch wipers encounter a calling line (or an idle line). This is accomplished by winding II of the rotary magnet which, as previously mentioned, causes the test relay to be iniiuenced Iinductively with the result that it is rapidly energized, causing the rotary magnet also to operate with slow action due to the fact that said winding II of the rotary magnet is connected to battery in the test circuit.

When after the end of the conversation the calling subscriber replaces his receiver, contact 17m is opened which causes the circuit of relays P and T to be cut oil' with the result that all the relays then are restored to normal.

Fig. 2 of the drawing illustrates diagrammatically in which manner the auxiliary winding III of the test relay P1, the windings I and II of which are disposed |in a test circuit extending over a wiper c2 of a switch, is inductively influenced on each step of the rotary magnet Dl with the aid of winding II of the rotary magnet, Dl, that is to say in which manner it is pre-magnetlized during each step executed by the switch for example during the setting of said switch. Relay P1 is energized in known manner when wiper c2 encounters a line to be seized and to which battery has been applied.

The arrangement may also be so made that the test relay is energized by means of the induced current only. In such ka case the C- lead of the seized lines has to be cut off and earth applied to the test circuit on both sides. The test relay, when energized, would then have to close its own locking circuit.

VThat is claimed is:

1. In a telephone system, a rotary switch, a driving magnet for setting said switch, a test relay, and means for causing said magnet to influence said test relay inductively during the setting movement.

2. A system as claimed in claim l, in which the driving magnet of the switch is provided with an auxiliary winding that is connected in series with the test relay.

3. A system as claimed in claim 1, in which the magnet is provided with an operating winding and an auxiliary winding that is ins ductively coupled with the operating winding and included in a circiut with the test relay so that the induced current generated by the opening of the circuit ,including the operating winding will accelerate the operation of the test relay when the switch is set to a definite position.

t. In a hunting switch, a rotary magnet, trunk lines accessible to said switch, means for operating said magnet to advance the wipers of said switch step-by-step to find one of said trunk lines, a test relay operated when said one trunk line is encountered to prevent further advancement of said wipers, and means associated with said rotary magnet for insuring the rapid operation of said test relay when said trunk line is encountered.

5. In a hunting switch, a magnet for advancing the wipers of said switch step-bystep, a line, means for operating said magnet to advance said wipers to find said line, a test relay for preventing further advancement of said wipers when said line is encountered, and means inductively related to said magnet for accelerating the operation of said test relay when said line is encountered by the wipers of the switch.

6. In a hunting switch, a rotary magnet, a subscribers line, a circuit including al primary winding on said magnet for advancing the wipers of said switch step-by-step to find said line, a test relay operated when said line is encountered to prevent further advancement of said wipers, and an inductive ly related secondary winding on said magnet included in a circuit with said test relay in which an induced current is generated when the wipers are advanced to said line to speed up the operation of said test relay.

7. In an automatic switch, a stepping magnet, a circuit including a first winding i of said magnet for operating the magnet, a test relay, and a circuit including a second winding of said magnet in which an induced current is generated when the circuit of the operating winding is opened for partially u ings for said magnet, means for closing a circuit for one of said windings to operate said magnet to advance the wipers, a test relay having a plurality of windings, a circuit including the other winding of the magnet and one winding of said test relay for partially energizing said test relay each time the wipers of said switch are advanced a step, and a circuit including the remaining windings of said test relay completed when the wipers of said switch are advanced to a. predetermined position for fully operating the partially energized test relay.

9. In an automatic telephone system, a calling subscribers line, an automatic stepping switch, means responsive to the initia- 

